WO2023238825A1 - Stratifié d'emballage et sac d'emballage - Google Patents

Stratifié d'emballage et sac d'emballage Download PDF

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Publication number
WO2023238825A1
WO2023238825A1 PCT/JP2023/020833 JP2023020833W WO2023238825A1 WO 2023238825 A1 WO2023238825 A1 WO 2023238825A1 JP 2023020833 W JP2023020833 W JP 2023020833W WO 2023238825 A1 WO2023238825 A1 WO 2023238825A1
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Prior art keywords
polypropylene film
layer
laminate
heat shrinkage
shrinkage rate
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PCT/JP2023/020833
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English (en)
Japanese (ja)
Inventor
靖方 小野
悠 荻原
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Ｔｏｐｐａｎホールディングス株式会社
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Priority to JP2023565430A priority Critical patent/JP7487851B2/ja
Publication of WO2023238825A1 publication Critical patent/WO2023238825A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/027—Thermal properties
    • B32B7/028—Heat-shrinkability
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
    • B65D65/38—Packaging materials of special type or form
    • B65D65/40—Applications of laminates for particular packaging purposes

Definitions

  • the present disclosure relates to a packaging laminate and a packaging bag.
  • polypropylene When changing packaging materials for retort pouches from conventional multi-material (composite material) packaging materials to monomaterial packaging materials that are essentially made of a single material, polypropylene should be used as the main component from the viewpoint of sealant properties. It is conceivable to use a laminate (PP monomaterial laminate). For example, Patent Document 1 below proposes a monomaterial packaging material using polypropylene.
  • the base material layer that is in direct contact with or close to the seal bar during bag making (heat sealing) must be heat resistant to prevent heat fusion with the seal bar.
  • Stretched polypropylene film is used to hold it.
  • the laminate may be deformed by heat, resulting in appearance defects such as curling and waving. Such deformation (distortion) may cause failure to grip the bag or failure to open the bag in the subsequent filling process, and may cause deterioration in transportability.
  • one aspect of the present disclosure aims to provide a laminate that is mainly composed of polypropylene and is less likely to be deformed by heat during bag making and less likely to curl due to high retort processing.
  • Another aspect of the present disclosure is to provide a package formed by bag-making the laminate described above.
  • a laminate for packaging in which 90% by mass or more of the total amount is polypropylene, a base layer containing a first polypropylene film; a sealant layer comprising a second polypropylene film;
  • the first polypropylene film is a stretched polypropylene film,
  • the first polypropylene film and the second polypropylene film are arranged so that their MD directions substantially match,
  • the heat shrinkage rate of the film in a predetermined direction is defined by the following formula (1)
  • the heat shrinkage rate R MD1 of the first polypropylene film in the MD direction is 10.0% or less
  • the heat shrinkage rate R TD1 of the first polypropylene film in the TD direction is 12.0% or less
  • the laminate, wherein the second polypropylene film has a heat shrinkage rate R TD2 in the TD direction that is smaller than the heat shrinkage rate R TD1 and is 0.5% or more.
  • Thermal contraction rate in the specified direction (%) ([Length in the specified direction before heating] - [
  • An intermediate layer including a third polypropylene film is provided between the base layer and the sealant layer,
  • the first polypropylene film, the second polypropylene film, and the third polypropylene film are arranged so that their MD directions substantially match,
  • the heat shrinkage rate of the film in a predetermined direction is defined by the above formula (1)
  • the thickness of the first polypropylene film and the third polypropylene film are each 18 to 30 ⁇ m, The laminate according to [7] or [8], wherein the second polypropylene film has a thickness of 50 to 100 ⁇ m.
  • the present disclosure it is possible to provide a laminate that is mainly composed of polypropylene and is less likely to be deformed by heat during bag making and less likely to curl due to high retort treatment. Moreover, according to another aspect of the present disclosure, it is an object of the present disclosure to provide a package formed by bag-making the above-mentioned laminate.
  • FIG. 1 is a schematic cross-sectional view showing a laminate according to one embodiment.
  • FIG. 2 is a schematic cross-sectional view showing a laminate according to another embodiment.
  • FIG. 3 is a schematic diagram showing a method for measuring the thermal shrinkage rate during oven heating.
  • FIG. 4 is a partially enlarged view of the laminate shown in FIG. 2.
  • FIGS. 5A to 5C are cross-sectional views of the sealed portion of the pouch, and are schematic diagrams showing the state of distortion of the pouch after heat sealing.
  • FIG. 6 is a schematic diagram showing a method for measuring the amount of curl during high retort processing.
  • a numerical range indicated using "-" indicates a range that includes the numerical values written before and after "-” as the minimum and maximum values, respectively. Furthermore, unless specifically specified, the units of numerical values written before and after " ⁇ " are the same.
  • the upper limit or lower limit of the numerical range of one step may be replaced with the upper limit or lower limit of the numerical range of another step. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples.
  • the upper limit values and lower limit values described individually can be combined arbitrarily.
  • the laminate 100A shown in FIG. 1 includes a base layer 11 and a sealant layer 12.
  • the base material layer 11 and the sealant layer 12 are each bonded with an adhesive layer S.
  • the base material layer 11 and the sealant layer 12 include a polypropylene film (polypropylene film).
  • polypropylene film refers to a film composed of polypropylene resin as a main component, and includes, for example, 90% by mass or more of polypropylene resin based on the total amount of the film.
  • first polypropylene film the polypropylene film contained in the base material layer 11
  • second polypropylene film the polypropylene film contained in the sealant layer 12
  • the first polypropylene film and the second polypropylene film are arranged so that their MD directions (Machine Directions) substantially match (that is, so that their angular difference is within ⁇ 15°). has been done.
  • MD directions Machine Directions
  • MD direction of the first polypropylene film and the MD direction of the second polypropylene film are approximately the same, and the TD direction (Transverse Direction) of the first polypropylene film is the same as the MD direction of the second polypropylene film. This substantially coincides with the TD direction of the polypropylene film.
  • the MD direction of the film can be determined by, for example, measuring the orientation angle using a phase difference measuring device (product name: KOBRA, manufactured by Oji Scientific Instruments Co., Ltd.), and the MD direction and the TD direction can be distinguished from the orientation angle.
  • a phase difference measuring device product name: KOBRA, manufactured by Oji Scientific Instruments Co., Ltd.
  • the direction in which the molecular chains are oriented is considered to be the TD direction.
  • the laminate 100B shown in FIG. 2 includes a base layer 11, an intermediate layer 13, and a sealant layer 12 in this order.
  • the base material layer 11 and the intermediate layer 13, as well as the intermediate layer 13 and the sealant layer 12, are each bonded with an adhesive layer S.
  • the intermediate layer 13 includes a polypropylene film.
  • the polypropylene film included in the intermediate layer 13 will be referred to as a "third polypropylene film.”
  • the details of the base material layer 11 and the sealant layer 12 are the same as those of the laminate 100A, and each includes a first polypropylene film and a second polypropylene film.
  • the first polypropylene film, the second polypropylene film, and the third polypropylene film are arranged so that their MD directions substantially match (that is, the angular difference is within ⁇ 15°). ) are located.
  • the MD direction of the first polypropylene film, the MD direction of the second polypropylene film, and the MD direction of the third polypropylene film are approximately the same, and the TD direction of the first polypropylene film and the second The TD direction of the polypropylene film and the TD direction of the third polypropylene film substantially match.
  • the thickness of the laminate (100A, 100B) may be 90 to 150 ⁇ m, 95 to 140 ⁇ m, or 100 to 130 ⁇ m.
  • the above laminates (100A, 100B) are laminates (packaging laminates) used as materials for packaging bags, and 90% or more of the total amount is polypropylene.
  • “90% of the total amount is polypropylene” has the same meaning as the content of polypropylene in the laminate (100A, 100B) is 90% by mass or more based on the total amount of the laminate. Therefore, the above-mentioned laminate has excellent recyclability and is suitably used as a (mono-material) packaging material made essentially of a single material.
  • the content of polypropylene in the laminate may be 95% by mass or more based on the total amount of the laminate.
  • the upper limit of the content of polypropylene is 100% by mass.
  • polypropylene content means the content of polypropylene resin contained in the laminate. However, if the above resin is a copolymer containing a copolymerized monomer other than propylene as a monomer unit, the amount of monomer units derived from the copolymerized monomer shall not be included in the content of polypropylene, and the monomer units derived from the propylene monomer shall not be included in the content of polypropylene.
  • the amount of polypropylene is defined as the polypropylene content.
  • the content of polypropylene can be measured according to Raman spectroscopy.
  • the heat shrinkage rate in a predetermined direction (MD direction or TD direction) of the film is defined by the following formula (1)
  • the heat shrinkage rate in the MD direction of the first polypropylene film R MD1 the heat shrinkage rate in the MD direction of the first polypropylene film
  • the heat shrinkage rate R TD1 in the TD direction of the first polypropylene film and the heat shrinkage rate R TD2 in the TD direction of the second polypropylene film satisfy the following condition (I), and in the laminate 100B shown in FIG.
  • the heat shrinkage rate R TD3 in the TD direction of the third polypropylene film satisfies the following condition (II).
  • the measurement of the heat shrinkage rate is performed according to the following procedure.
  • a measurement sample 200 is obtained by cutting out a film to be measured into a size of 200 mm x 200 mm.
  • two straight lines L1 and L2 with a length of 120 mm or more parallel to the TD direction of the measurement sample 200 are written on the surface of the measurement sample 200 with an interval of 100 mm.
  • two straight lines L3 and L4 with a length of 120 mm or more parallel to the MD direction of the measurement sample 200 are written on the surface of the measurement sample 200 with an interval of 100 mm.
  • d As shown in FIG.
  • scales N1 to N7 are written at 7 locations at 20 mm intervals on each of the straight lines L1 to L4.
  • the scales of the straight lines L1 and L2 are set so that the straight line is parallel to the MD direction. Align the position.
  • the scales of the straight lines L3 and L4 are set so that the straight line is parallel to the TD direction. Align.
  • the heat shrinkage rate in the MD direction at each position of the scale N2 to N7 is determined, and the average value of the heat shrinkage rate in the MD direction determined at each position of N1 to N7 is measured.
  • Shrinkage rate R MD (g) The linear distance between the scale N1 of the straight line L3 (the intersection of L3 and N1) and the scale N1 of the straight line L4 (the intersection of L4 and N1) is taken as the length in the TD direction, and is measured before and after heating, and the above formula (1 ), determine the heat shrinkage rate in the TD direction.
  • the thermal contraction rate in the TD direction at each position of the scale N2 to N7 is determined, and the average value of the thermal contraction rate in the TD direction determined at each position of N1 to N7 is measured.
  • Shrinkage rate R TD (g) The linear distance between the scale N1 of the straight line L3 (the intersection of L3 and N1) and the scale N1 of the straight line L4 (the intersection of L4 and N1) is taken as the length
  • the heat shrinkage rate of the film does not substantially change during the manufacturing process of the laminate, so by using a film that exhibits the above heat shrinkage rate when the heat shrinkage rate is measured alone, the above laminates 100A and 100B can be obtained. I can do it.
  • the base material layer is the part that directly contacts or is close to the heat seal bar during bag making (heat sealing), and is the part that is particularly exposed to heat among the layers of the laminate, so in conventional PP monomaterial laminates, It is thought that deformation (distortion) such as curling and waving occurred during bag making (that is, heat sealing) due to heat shrinkage of the base material layer.
  • packaging materials for retort pouches use a sealant layer that has a high melting point to prevent opening under retort conditions, so higher temperatures tend to be applied during heat sealing, making the above deformation more likely to occur.
  • the heat shrinkage rates R MD1 and R TD1 are sufficiently small. , hard to cause deformation due to heat during bag making. Furthermore, for the above reasons, the laminates (100A, 100B) are less likely to wrinkle during bag making. Therefore, according to the laminates (100A, 100B), it is possible to easily obtain a package that has less deformation (distortion) and wrinkles, has a good appearance, and has excellent transportability and workability when enclosing contents. can.
  • the sealant layer of conventional PP monomaterial laminates a material (sealant film) that has almost no heat shrinkage is normally used, but in the above laminates (100A, 100B), as mentioned above, Since the shrinkage rate R TD2 (heat shrinkage rate in the TD direction of the second polypropylene film) is 0.5% or more, curling due to retort treatment at a high temperature of 125° C. or higher (high retort treatment) is unlikely to occur. Therefore, the above laminate can be suitably used for retort pouches.
  • the base material layer 11 is a layer that serves as one of the supports, and includes a first polypropylene film.
  • the base material layer 11 is the outermost layer (outermost layer) of the laminate (100A, 100B).
  • the polypropylene resin constituting the first polypropylene film may be a homopolymer of propylene, or a copolymer of propylene and another comonomer.
  • the copolymer include propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene- ⁇ -olefin copolymer, and the like.
  • the polypropylene resin may be acid-modified polypropylene obtained by graft-modifying polypropylene using an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like.
  • the first polypropylene film may further contain various additives such as flame retardants, slip agents, anti-blocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and the like.
  • the first polypropylene film is a stretched polypropylene film. Since a stretched polypropylene film has excellent heat resistance, when the first polypropylene film is a stretched polypropylene film, it is possible to prevent the base material layer from being thermally fused to the heat seal bar.
  • the stretched polypropylene film may be a film stretched by a known method such as inflation stretching, uniaxial stretching, biaxial stretching, or the like.
  • the stretched polypropylene film may be a biaxially stretched polypropylene film in that the above heat shrinkage rates (R MD1 and R TD1 ) can be easily obtained.
  • the surface of the first polypropylene film may be subjected to various pretreatments such as corona treatment, plasma treatment, and flame treatment.
  • the thickness of the first polypropylene film is not particularly limited. Depending on the application, the thickness can be set to 6 to 200 ⁇ m, but from the viewpoint of reducing material to reduce environmental impact, and from the viewpoint of obtaining excellent heat resistance, impact resistance, and excellent gas barrier properties, It may be 9-60 ⁇ m, 18-60 ⁇ m or 9-50 ⁇ m. The thinner the base material layer is, the more likely the laminate is to shrink during heat sealing. However, in the laminate according to this embodiment, since a base material layer that satisfies specific conditions is used, the thickness of the base material layer is Even if the thickness is thin, shrinkage of the laminate can be suppressed. Therefore, the thickness of the first polypropylene film may be less than 25 ⁇ m, and may be 20 ⁇ m or less.
  • the thickness of the first polypropylene film in the laminate 100A is from 36 to 36 mm from the viewpoint of material reduction to reduce environmental impact, and from the viewpoint of obtaining excellent heat resistance, excellent impact resistance, and excellent gas barrier properties. It may be 60 ⁇ m, 38-55 ⁇ m or 40-50 ⁇ m.
  • the thickness of the first polypropylene film in the laminate 100B is set to 12 to 12, from the viewpoint of material reduction to reduce environmental impact, and from the viewpoint of obtaining excellent heat resistance, excellent impact resistance, and excellent gas barrier properties. It may be 38 ⁇ m, 18-30 ⁇ m or 20-25 ⁇ m.
  • the thickness of the first polypropylene film may be 10 to 50% of the total thickness of the laminate.
  • the thickness of the first polypropylene film in the laminate 100A is determined from the viewpoint of material reduction to reduce environmental impact, and from the viewpoint of obtaining excellent heat resistance, excellent impact resistance, and excellent gas barrier properties. may be 20-60%, 23-50% or 25-40% of the total thickness.
  • the thickness of the first polypropylene film in the laminate 100B is determined from the viewpoint of material reduction to reduce environmental impact, and from the viewpoint of obtaining excellent heat resistance, excellent impact resistance, and excellent gas barrier properties. may be 10 to 50%, 13 to 45% or 15 to 40% of the total thickness.
  • the thickness of the first polypropylene film may be 90% or more of the thickness of the base layer 11, and the base layer 11 may consist only of the first polypropylene film.
  • the heat shrinkage rate R MD1 of the first polypropylene film in the MD direction is 10.0% or less, and from the viewpoint of further suppressing deformation due to heat during bag making and curling due to high retort processing, it is 8.0% or less, It may be 7.0% or less or 5.0% or less.
  • the heat shrinkage rate R MD1 may be greater than the heat shrinkage rate R MD2 in the MD direction of the second polypropylene film. Since the first polypropylene film will be the outermost layer after bag making, it is also required to have mechanical properties (firmness, tensile strength, printability) and optical properties (transparency, gloss).
  • the heat shrinkage rate R MD1 of the first polypropylene film may be, for example, 1.0% or more, or 3.0% or more. That is, the heat shrinkage rate R MD1 may be 1.0 to 10.0%, or may be 3.0 to 10.0%.
  • the heat shrinkage rate R TD1 of the first polypropylene film in the TD direction is 12.0% or less, and from the viewpoint of further suppressing deformation due to heat during bag making and curling due to high retort treatment, it is 10.0% or less, It may be 8.0% or less or 7.0% or less.
  • the heat shrinkage rate R TD1 may be, for example, 1.0% or more, or 3.0% or more. That is, the heat shrinkage rate R TD1 may be 1.0 to 12.0%, or may be 3.0 to 12.0%.
  • both the heat shrinkage rate R MD1 and the heat shrinkage rate R TD1 may be 7.0% or less.
  • the first polypropylene film having heat shrinkage rates R MD1 and R TD1 within the above ranges can be formed by stretching (particularly biaxial stretching) or by using a resin with a high melting point as the type of polypropylene resin that is the constituent material of the film. It can be obtained by using, etc.
  • the crystallinity of the first polypropylene film measured by oblique incidence X-ray diffraction may be 80% or more in both the MD direction and the TD direction.
  • the crystallinity may be 86% or more in one direction and 80% or more in the other direction.
  • the crystallinity of the first polypropylene film in the MD direction and the TD direction can be measured by oblique incidence X-ray diffraction method under the following conditions.
  • the X-ray irradiation device and the detector are arranged in a direction perpendicular to the MD direction, and when measuring the crystallinity degree in the TD direction, The measurement is performed by arranging the X-ray irradiation device and the detector so that they are aligned in a direction perpendicular to the TD direction.
  • Measuring device X-ray diffraction device (manufactured by Rigaku Co., Ltd., product name: RINT TTR III)
  • Optical system Parallel method (detector: scintillation counter, application: small angle, target: sample surface) Scanning axis: 2 ⁇ / ⁇ Measurement method: continuous counting unit: cps Starting angle: 3° (approximate) End angle: 35° Sampling width: 0.02° Scan speed: 4°/min Voltage: 50kV Current: 300mA Divergent vertical slit: 10mm Scattering slit: Released Light receiving slit: Released Calculation method of crystallinity: Peak separation method Analysis software: MDI JADE PRO/Version 8.6 In the diffraction pattern obtained by X-ray diffraction, a profile fitting technique is used to separate the background, amorphous components, and crystalline components.
  • the degree of crystallinity is calculated from the following formula using the area under the curve (integrated intensity) of the diffraction curve of the amorphous component and the crystalline component separated from the total scattering curve.
  • Xc Ic/(Ic+Ia) ⁇ 100
  • Ia Amorphous scattering intensity
  • the crystallinity of the first polypropylene film in the MD direction and the TD direction is 80% or more, shrinkage of the laminate can be further suppressed in the heat sealing process when bag-making the laminate. As a result, it becomes easier to suppress deformation and wrinkles of the packaging bag, as well as deterioration of physical properties such as pattern deviation and lamination strength of the packaging bag. Furthermore, since one of the crystallinities in the MD direction and the TD direction in the first polypropylene film is 86% or more and the other is 80% or more, it is possible to It is possible to suppress the occurrence of whitening. Therefore, it is possible to prevent poor appearance and poor performance of the resulting packaging bag, and also to prevent troubles during transportation and when filling the bag.
  • one of the crystallinities in the MD direction and the TD direction of the first polypropylene film may be 90% or more, and the other may be 84% or more.
  • the first polypropylene film may have a crystallinity of 80% or more, 84% or more, or 86% or more in the MD direction, and a crystallinity of 80% or more or 84% or more in the TD direction.
  • the upper limit of the degree of crystallinity is not particularly limited in either the MD direction or the TD direction, but may be, for example, 95% or less.
  • the crystallinity of the first polypropylene film in the MD direction and the TD direction can be adjusted by, for example, stretching conditions, molecular weight, cooling temperature, blending of a crystal nucleating agent, etc.
  • the first polypropylene film whose crystallinity in the MD direction and the TD direction is 80% or more the following effects can be achieved in the laminate manufacturing process.
  • the laminate manufacturing process involves many heat-intensive processes such as corona treatment and oven processes, so there is a risk that the base material layer may shrink during processing, causing misalignment of patterns and variations in laminate strength. be.
  • the first polypropylene film with a crystallinity of 80% or more in the MD and TD directions is used, the high crystallinity suppresses the shrinkage of the base layer and prevents the positional displacement of patterns, etc. It is possible to suppress the occurrence of variations in laminate strength.
  • the oven temperature after printing or adhesive coating can be set high, so that residual solvent This makes it possible to reduce the amount of damage and speed up the work, thereby improving the productivity of the laminate.
  • the difference between the crystallinity in the MD direction and the crystallinity in the TD direction measured by oblique incidence X-ray diffraction may be 4% or more and 10% or less. Good too. The smaller the difference between the crystallinity in the MD direction and the crystallinity in the TD direction, the more consistent the crystals in the base layer are oriented, and the durability is improved.
  • the packaging bag may be deformed, whitened, and wrinkled, and the packaging bag may be It is possible to suppress the occurrence of pattern deviation, deterioration of physical properties such as lamination strength, and deformation of the packaging bag. From the viewpoint of obtaining the above effect at a higher level, the difference between the crystallinity in the MD direction and the crystallinity in the TD direction may be 8% or less.
  • the above-mentioned “crystallinity degree in the MD direction and TD direction in the first polypropylene film” is “crystallinity degree in the MD direction and TD direction in the base material layer” It can also be read as When the crystallinity of the base material layer in the MD direction and the TD direction is within the above range, the above effects tend to be more pronounced.
  • the first polypropylene film has at least one melting peak observed below 163°C when differential scanning calorimetry is performed under the conditions (ii) below after heat treatment under the conditions (i) below. It may be.
  • a plurality of the above melting peaks it is sufficient that at least one of them is observed at a temperature below 163°C, and other melting peaks may be observed at a temperature above 163°C. It may be observed below °C.
  • the temperature at which 30% or more of the entire first polypropylene film melts is preferably less than 163°C. Whether 30% or more of the entire first polypropylene film is melted can be determined by comparing the melting peak areas.
  • the number of melting peaks that may be observed may be one, and there may be no melting peak observed above 163°C.
  • the temperature was raised from 25°C to 230°C at a rate of 10°C/min, held at 230°C for 2 minutes, and then lowered from 230°C to 25°C at a rate of 10°C/min, and at 25°C for 5 minutes. Hold for minutes.
  • (ii) Raise the temperature from 25°C to 230°C at a rate of 10°C/min and hold at 230°C for 5 minutes.
  • the melting peak temperature measured under the above conditions indicates the melting point of the first polypropylene film material itself (hereinafter also referred to as "melting point after heat treatment") from which the effects of stretching etc. have been removed by heat treatment.
  • melting point after heat treatment the melting point of the first polypropylene film material itself
  • the base material layer may have a melting point after heat treatment measured under the above conditions of less than 163°C.
  • the first polypropylene film may have at least one melting peak observed at 167° C. or higher when differential scanning calorimetry is performed under the conditions (iii) below.
  • a plurality of the above melting peaks may be observed, at least one of which may be observed at a temperature of 167°C or higher, and at least one other melting peak may be observed at a temperature below 167°C.
  • (iii) Raise the temperature from 25°C to 230°C at a rate of 10°C/min and hold at 230°C for 2 minutes.
  • the melting peak temperature measured under the above conditions indicates the melting point (hereinafter also referred to as "melting point before heat treatment") of the first polypropylene film that remains unaffected by stretching and the like. Since the melting point of the first polypropylene film before heat treatment is 167°C or higher, the heat resistance of the first polypropylene film in the state before heat treatment is improved, and distortion, whitening, and wrinkles occur during bag making of the laminate. It is possible to further suppress the occurrence of From the viewpoint that such an effect is more easily obtained, the base material layer may have a melting point of less than 163° C. before heat treatment measured under the above conditions.
  • the melting point after the heat treatment can be adjusted by, for example, the molecular weight, stereoregularity (isotactic mesopentad fraction), blending of the crystal nucleating agent, etc. Further, the melting point before heat treatment can be adjusted by, for example, stretching conditions, cooling temperature, blending of a crystal nucleating agent, etc.
  • the thickness of the base layer 11 may be within the range exemplified as the thickness of the first polypropylene film above.
  • the sealant layer 12 is a layer that provides sealing properties by heat sealing to the laminate, and includes a second polypropylene film.
  • the polypropylene resin constituting the second polypropylene film may be a homopolymer of propylene or a copolymer of propylene and another comonomer. Examples of the copolymer include propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene- ⁇ -olefin copolymer, and the like.
  • the polypropylene resin may be acid-modified polypropylene obtained by graft-modifying polypropylene using an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like.
  • the second polypropylene film may further contain various additives such as flame retardants, slip agents, anti-blocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and the like.
  • the second polypropylene film may be a stretched polypropylene film, it is preferably a non-stretched polypropylene film from the viewpoint of improving sealing performance by heat sealing.
  • the thickness of the second polypropylene film is determined by the mass of the contents, the shape of the packaging bag, etc.
  • the thickness of the second polypropylene film may be 30 to 150 ⁇ m, 40 to 100 ⁇ m, 50 to 100 ⁇ m, 40 to 90 ⁇ m, 30 to 80 ⁇ m, or 50 ⁇ m, from the viewpoint of improving heat sealability and impact resistance in a well-balanced manner. It may be ⁇ 80 ⁇ m.
  • the thickness of the second polypropylene film may be 35 to 75%, 40 to 70% or 45 to 65% of the total thickness of the laminate, from the viewpoint of improving heat sealability and impact resistance in a well-balanced manner. There may be.
  • the thickness of the second polypropylene film may be 90% or more of the thickness of the sealant layer 12, and the sealant layer 12 may consist only of the second polypropylene film.
  • the heat shrinkage rate R MD2 of the second polypropylene film in the MD direction is preferably 0.5% or more from the viewpoint of further suppressing curling due to high retort treatment.
  • the heat shrinkage rate R MD2 may be smaller than the heat shrinkage rate R MD1 in the MD direction of the first polypropylene film, and may be, for example, 5.0% or less.
  • the heat shrinkage rate R TD2 of the second polypropylene film in the TD direction is 0.5% or more.
  • the heat shrinkage rate R TD2 may be smaller than the heat shrinkage rate R TD1 in the TD direction of the first polypropylene film, for example, 5.0% or less.
  • the second polypropylene film having heat shrinkage rates R MD2 and R TD2 within the above ranges can be obtained by non-stretching, etc.
  • the difference between the heat shrinkage rate R MD1 and the heat shrinkage rate R MD2 (R MD1 - R MD2 ), the better .
  • the difference (R MD1 - R MD2 ) is preferably 8% or less (for example, 1% to 8%), and the difference (R TD1 - R TD2 ) is preferably 8% or less (for example, , 1% to 8%).
  • the thickness of the sealant layer 12 may be within the range exemplified as the thickness of the second polypropylene film above.
  • the sealant layer 12 may be formed by, for example, a dry lamination method in which the second polypropylene film is bonded to another layer with an adhesive (for example, a one-component curing type or a two-component curing type urethane adhesive), Non-solvent dry lamination method, in which the second polypropylene film is laminated to another layer using a solvent-free adhesive, and extrusion lamination method, in which the constituent materials of the second polypropylene film are heated and melted, extruded into a curtain shape, and laminated together. It can be laminated on other layers by known lamination methods. Among the above-mentioned formation methods, the dry lamination method is preferred because of its high resistance to high-retort treatment. On the other hand, if the packaging bag is used for processing at a temperature of 85° C. or lower, the lamination method is not particularly limited.
  • Intermediate layer 13 is located between base layer 11 and sealant layer 12.
  • the laminate 100B is less likely to deform during bag making than the laminate 100A which does not include the intermediate layer 13.
  • the intermediate layer 13 includes a third polypropylene film.
  • the third polypropylene film may be an unstretched polypropylene film or a stretched polypropylene film.
  • Examples of the stretched polypropylene film and the unstretched polypropylene film include the polypropylene films exemplified in the first polypropylene film and the second polypropylene film. From the viewpoints of impact resistance, heat resistance, water resistance, dimensional stability, etc., the third polypropylene film is preferably a stretched film.
  • the thickness of the third polypropylene film is 18 to 30 ⁇ m from the viewpoint of material reduction to reduce environmental impact, and from the viewpoint of obtaining excellent heat resistance, excellent impact resistance, and excellent gas barrier properties. good.
  • the thickness of the third polypropylene film is determined based on the total thickness of the laminate, from the viewpoint of material reduction to reduce environmental impact, and from the viewpoint of obtaining excellent heat resistance, excellent impact resistance, and excellent gas barrier properties. It may be 5-30%.
  • the thickness of the third polypropylene film may be 90% or more of the thickness of the intermediate layer 13, and the intermediate layer 13 may consist only of the third polypropylene film.
  • the total thickness of the third polypropylene film and the first polypropylene film may be 36 to 60 ⁇ m.
  • the total thickness of the base layer 11 and the intermediate layer 13 may be within the above range.
  • the ratio of the thickness of the third polypropylene film to the thickness of the first polypropylene film may be 1.00 or more, and 1. It may be more than 00, 1.25 or more, or 1.50 or more.
  • the ratio may be, for example, 4.0 or less. From the same viewpoint, the ratio of the thickness of the intermediate layer to the thickness of the base material layer may also be within the above range.
  • the heat shrinkage rate R MD3 of the third polypropylene film in the MD direction is preferably 10.0% or less, and 8.0% from the viewpoint of further suppressing deformation due to heat during bag making and curling due to high retort treatment. % or less, 7.0% or less, or 5.0% or less.
  • the heat shrinkage rate R MD3 of the third polypropylene film in the MD direction may be 12.0% or less or 14.0% or less.
  • the heat shrinkage rate R MD3 may be greater than the heat shrinkage rate R MD2 in the MD direction of the second polypropylene film, and may be, for example, 1.0% or more. That is, the heat shrinkage rate R MD3 of the third polypropylene film may be, for example, 1.0 to 10.0%.
  • the heat shrinkage rate R MD3 may be 3.0% or more. stomach.
  • the heat shrinkage rate R TD3 of the third polypropylene film in the TD direction is 12.0% or less, and from the viewpoint of further suppressing deformation due to heat during bag making and curling due to high retort treatment, it is 10.0% or less, It may be 8.0% or less or 7.0% or less.
  • the heat shrinkage rate R TD3 is larger than the heat shrinkage rate R TD2 in the TD direction of the second polypropylene film, and may be, for example, 1.0% or more, or 3.0% or more. That is, the heat shrinkage rate R TD3 may be 1.0 to 12.0%, or may be 3.0 to 12.0%.
  • the difference between the heat shrinkage rate R MD3 and the heat shrinkage rate R MD2 (R MD3 - R MD2 ), the better .
  • the difference (R MD3 - R MD2 ) is preferably 8.0% or less (for example, 1.0% to 8.0%), and the difference (R TD3 - R TD2 ) is preferably 8.0% or less (for example, 1.0% to 8.0%). is 8.0% or less (for example, 1.0% to 8.0%).
  • the thickness of the intermediate layer 13 may be within the range exemplified as the thickness of the third polypropylene film above.
  • the adhesive material constituting the adhesive layer S examples include polyester-isocyanate resins, urethane resins, and polyether resins.
  • the adhesive layer S is preferably a layer made of a cured product of a two-component urethane adhesive. From an environmental standpoint, the adhesive may not contain 3-glycidyloxypropyltrimethoxysilane (GPTMS).
  • the thickness of the adhesive layer S is not particularly limited, but may be, for example, 0.5 to 5 ⁇ m, or 2 to 3 ⁇ m.
  • the thickness of the adhesive layer S may be 0.5 to 4 ⁇ m from the viewpoint of ensuring sufficient adhesiveness while keeping the content of polypropylene in the laminate at 90% by mass or more.
  • each layer is not limited to the above.
  • a layer other than the layer consisting of a polypropylene film, a second polypropylene film, and a third polypropylene film may be included.
  • layers other than the layer made of polypropylene film include a coating layer such as an easily adhesive layer, an inorganic oxide layer, a gas barrier coating layer, a printing layer, and the like.
  • a coating layer 16 As an example, a partially enlarged view of the laminate 100B is shown in FIG. In the laminate 100B, a coating layer 16, an inorganic oxide layer 17, and a gas barrier coating layer 18 are laminated in this order on the third polypropylene film 15.
  • An intermediate layer 13 consisting of an oxide layer 17 and a gas barrier coating layer 18 and a base layer 11 consisting of a first polypropylene film 14 are laminated with an adhesive layer S interposed therebetween.
  • Layers other than the layer consisting of the polypropylene film described above may be provided on at least one surface of the first polypropylene film and/or on at least one surface of the third polypropylene film; From the viewpoint of making the film less susceptible to the effects of polypropylene, as shown in FIG. 4, it is preferable to provide the polypropylene film between the first polypropylene film and the third polypropylene film.
  • the coating layer, inorganic oxide layer, gas barrier coating layer, and printing layer that may be included in the base layer 11 and/or the intermediate layer 13 will be described.
  • the coat layer may be an anchor coat layer (also referred to as an "adhesion layer") provided between the polypropylene film and the inorganic oxide layer in order to improve the adhesion between the polypropylene film and the inorganic oxide layer. .
  • an anchor coat layer By providing the anchor coat layer between the polypropylene film and the inorganic oxide layer, the two effects of improving the adhesion between the polypropylene film and the inorganic oxide layer and improving the smoothness of the surface of the polypropylene film are obtained. be able to. In addition, by improving the smoothness, it becomes easier to form an inorganic oxide layer uniformly without defects, and it becomes easier to exhibit high barrier properties.
  • the anchor coat layer can be formed using an anchor coat agent.
  • anchor coating agent examples include acrylic polyurethane resins, polyester polyurethane resins, polyether polyurethane resins, polyurethane resins formed from acid group-containing polyurethanes, and polyamines.
  • acrylic polyurethane resins and polyester polyurethane resins are preferred from the viewpoints of heat resistance and interlayer adhesive strength.
  • the thickness of the coating layer is not particularly limited, but is preferably in the range of 0.01 to 5 ⁇ m, more preferably in the range of 0.03 to 3 ⁇ m, and particularly in the range of 0.05 to 2 ⁇ m. preferable.
  • the thickness of the coating layer is at least the above lower limit, more sufficient interlayer adhesive strength tends to be obtained, while when it is at most the above upper limit, desired gas barrier properties tend to be easily expressed.
  • any known coating method can be used without any particular restriction, and examples thereof include dipping method (dipping method); methods using spray, coater, printing machine, brush, etc. .
  • the types of coaters and printing machines used in these methods and their coating methods include gravure coaters such as direct gravure method, reverse gravure method, kiss reverse gravure method, and offset gravure method, reverse roll coater, and microgravure. Examples include a coater, a chamber doctor coater, an air knife coater, a dip coater, a bar coater, a comma coater, and a die coater.
  • the coating amount of the coating layer is preferably 0.01 to 5 g/m 2 , and preferably 0.03 to 3 g/m 2 in mass per 1 m 2 after coating and drying the anchor coating agent. It is more preferable.
  • mass per 1 m 2 after coating and drying the anchor coating agent is above the above lower limit, film formation tends to be sufficient.On the other hand, when it is below the above upper limit, it is sufficiently easy to dry and the solvent is removed. It tends to be difficult to remain.
  • Methods for drying the coat layer include, but are not limited to, natural drying, drying in an oven set at a predetermined temperature, a dryer attached to the coater, such as an arch dryer, a floating dryer, a drum dryer, A method using an infrared dryer or the like can be mentioned. Further, the drying conditions can be appropriately selected depending on the drying method. For example, in the case of drying in an oven, it is preferable to dry at a temperature of 60 to 100° C. for about 1 second to 2 minutes.
  • a polyvinyl alcohol resin can also be used instead of the above polyurethane resin.
  • the polyvinyl alcohol resin may be any resin having a vinyl alcohol unit formed by saponifying a vinyl ester unit, and examples thereof include polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH).
  • PVA polyvinyl alcohol
  • EVOH ethylene-vinyl alcohol copolymer
  • methods for forming the coat layer include coating using a polyvinyl alcohol resin solution, multilayer extrusion, and the like.
  • the inorganic oxide layer contributes to improving gas barrier properties.
  • the inorganic oxide contained in the inorganic oxide layer include aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. From the viewpoint of transparency and barrier properties, the inorganic oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Further, from the viewpoint of excellent tensile stretchability during processing, it is preferable that the inorganic oxide layer is a layer using silicon oxide. By using an inorganic oxide layer, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the laminate.
  • the O/Si ratio of the inorganic oxide layer is 1.7 or more.
  • the metal Si content is suppressed and good transparency is easily obtained.
  • the O/Si ratio is preferably 2.0 or less.
  • the crystallinity of SiO becomes high and the inorganic oxide layer can be prevented from becoming too hard, and good tensile resistance can be obtained. Thereby, it is possible to suppress the occurrence of cracks in the inorganic oxide layer when laminating the gas barrier coating layer.
  • the base layer or intermediate layer may shrink due to heat during boiling or retort processing, but if the O/Si ratio is 2.0 or less, the inorganic oxide layer will shrink. It is possible to easily follow this and suppress the deterioration of barrier properties. From the viewpoint of obtaining these effects more fully, the O/Si ratio of the inorganic oxide layer is preferably 1.75 or more and 1.9 or less, and more preferably 1.8 or more and 1.85 or less.
  • the O/Si ratio of the inorganic oxide layer can be determined by X-ray photoelectron spectroscopy (XPS).
  • XPS X-ray photoelectron spectroscopy
  • the measurement device is an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV), the X-ray source is non-monochromatic MgK ⁇ (1253.6eV), and the X-ray source is 100W (10kV-10mA). ) can be measured using the X-ray output.
  • Relative sensitivity factors of 2.28 for O1s and 0.9 for Si2p can be used for quantitative analysis to determine the O/Si ratio, respectively.
  • the thickness of the inorganic oxide layer is preferably 10 nm or more and 50 nm or less.
  • the film thickness is 10 nm or more, sufficient water vapor barrier properties can be obtained.
  • the film thickness is 50 nm or less, it is possible to suppress the occurrence of cracks due to deformation due to internal stress of the thin film, and to suppress a decrease in water vapor barrier properties. It should be noted that if the film thickness exceeds 50 nm, the cost tends to increase due to an increase in the amount of materials used, a longer film formation time, etc., which is not preferable from an economic point of view. From the same viewpoint as above, the thickness of the inorganic oxide layer is more preferably 20 nm or more and 40 nm or less.
  • the inorganic oxide layer can be formed, for example, by vacuum film formation.
  • a physical vapor deposition method or a chemical vapor deposition method can be used.
  • the physical vapor deposition method include, but are not limited to, a vacuum evaporation method, a sputtering method, an ion plating method, and the like.
  • the chemical vapor deposition method include, but are not limited to, a thermal CVD method, a plasma CVD method, a photo CVD method, and the like.
  • the above vacuum film formation methods include resistance heating vacuum evaporation method, EB (Electron Beam) heating vacuum evaporation method, induction heating vacuum evaporation method, sputtering method, reactive sputtering method, dual magnetron sputtering method, and plasma chemical vapor deposition method. (PECVD method) etc. are particularly preferably used. However, in terms of productivity, the vacuum deposition method is currently the best.
  • a heating means for the vacuum evaporation method it is preferable to use one of an electron beam heating method, a resistance heating method, and an induction heating method.
  • the gas barrier coating layer protects the inorganic oxide layer, contributes to improving gas barrier properties, and exhibits high gas barrier properties due to a synergistic effect with the inorganic oxide layer.
  • the gas barrier coating layer is, for example, a composition for forming a gas barrier coating layer containing at least one member selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide, a silane coupling agent, and a hydrolyzate thereof.
  • the layer may be formed using.
  • the gas barrier coating layer is mainly composed of an aqueous solution or a water/alcohol mixed solution containing at least one selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide, a silane coupling agent, and a hydrolyzate thereof. It can be formed using a composition for forming a gas barrier coating layer (hereinafter also referred to as a coating agent).
  • the coating agent preferably contains at least a silane coupling agent or a hydrolyzate thereof, and preferably contains a hydroxyl group-containing polymer compound, a metal alkoxide and It is more preferable to contain at least one selected from the group consisting of hydrolysates thereof, a silane coupling agent or a hydrolyzate thereof, and a hydroxyl group-containing polymer compound or a hydrolyzate thereof, a metal alkoxide or It is more preferable to contain a hydrolyzate thereof and a silane coupling agent or a hydrolyzate thereof.
  • the coating agent can be prepared by directly or pre-hydrolyzing a metal alkoxide and a silane coupling agent in a solution in which a water-soluble polymer containing a hydroxyl group is dissolved in an aqueous (water or water/alcohol mixed) solvent. It can be prepared by mixing those that have been subjected to a treatment such as oxidation.
  • Hydroxyl group-containing polymer compounds used in the coating agent include polyvinyl alcohol, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, sodium alginate, and the like. Among these, it is preferable to use polyvinyl alcohol (PVA) as a coating agent for the gas barrier coating layer since it has particularly excellent gas barrier properties.
  • PVA polyvinyl alcohol
  • metal alkoxide examples include tetraethoxysilane [Si(OC 2 H 5 ) 4 ], triisopropoxyaluminum [Al(O-2'-C 3 H 7 ) 3 ], and the like. Tetraethoxysilane and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.
  • silane coupling agent examples include vinyltrimethoxysilane, ⁇ -chloropropylmethyldimethoxysilane, ⁇ -chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, ⁇ -methacryloxypropyltrimethoxysilane, ⁇ -methacryloxypropyl Examples include methyldimethoxysilane.
  • the silane coupling agent may be a multimer of these.
  • additives such as isocyanate compounds, dispersants, stabilizers, viscosity modifiers, and colorants can be added to the coating agent as long as the gas barrier properties are not impaired.
  • An acid catalyst, an alkali catalyst, a photoheavy initiator, etc. may be added to the coating agent as necessary.
  • the thickness of the gas barrier coating layer is preferably 0.5 to 4 ⁇ m, more preferably 0.5 to 3 ⁇ m, from the viewpoint of obtaining excellent gas barrier properties while maintaining the polypropylene content in the laminate at 90% by mass or more. More preferably, the thickness is 1 ⁇ m or more and 3 ⁇ m or less.
  • the thickness of the gas barrier coating layer may be 50 to 1000 nm or 100 to 500 nm. When the thickness of the gas barrier coating layer is 50 nm or more, more sufficient gas barrier properties tend to be obtained, and when the thickness of the gas barrier coating layer is 1000 nm or less, sufficient flexibility tends to be maintained. There is.
  • Coating agents for forming the gas barrier coating layer include, for example, a dipping method, a roll coating method, a gravure coating method, a reverse gravure coating method, an air knife coating method, a comma coating method, a die coating method, a screen printing method, a spray coating method, It can be applied by a gravure offset method or the like.
  • a coating formed by applying this coating agent can be dried by, for example, a hot air drying method, a hot roll drying method, a high frequency irradiation method, an infrared irradiation method, a UV irradiation method, or a combination thereof.
  • the temperature at which the coating film is dried can be, for example, 50 to 150°C, preferably 70 to 100°C.
  • the printing layer may be provided at a position visible from the outside of the laminate for the purpose of displaying information about the contents, identifying the contents, improving concealment, or improving the design of the packaging bag.
  • the printing method and printing ink are not particularly limited, and are appropriately selected from among known printing methods and printing inks, taking into consideration suitability for printing onto a film, design characteristics such as color tone, adhesion, safety as a food container, etc. Ru.
  • a gravure printing method, an offset printing method, a gravure offset printing method, a flexo printing method, an inkjet printing method, etc. can be used.
  • the gravure printing method can be preferably used from the viewpoint of productivity and high definition of the image.
  • the surface of the layer on which the printed layer is to be provided may be subjected to various pretreatments such as corona treatment, plasma treatment, flame treatment, etc., and a coating layer such as an easy-to-adhesion layer may be provided.
  • the surface of the layer provided with the printing layer may be the surface of the polypropylene film (the first polypropylene film or the third polypropylene film), or may be the surface of the gas barrier coating layer.
  • the thickness of the printed layer may be between 0.1 and 5 ⁇ m.
  • each layer is bonded with an adhesive layer S, but the laminate does not need to include the adhesive layer S.
  • the base material layer 11 and the sealant layer 12 of the laminate 100A may be directly bonded to each other, and the base material layer 11 and the intermediate layer 13 and/or the intermediate layer 13 and the sealant layer 12 of the laminate 100B may be directly bonded to each other. It may be directly bonded.
  • the base layer and the intermediate layer are bonded together with an adhesive layer having a thickness of 0.5 to 4 ⁇ m. Further, from the same viewpoint, it is preferable that the intermediate layer and the sealant layer are bonded together by an adhesive layer having a thickness of 0.5 to 4 ⁇ m.
  • the packaging bag is made by bag-making the above-mentioned laminate.
  • the package may be made into a bag shape by, for example, folding one laminate in half so that the sealant layers face each other, and then heat-sealing the three sides. It is also possible to form a bag shape by stacking two laminates so that the sealant layers face each other and then heat sealing them on four sides. It may also be a self-supporting standing pouch that is stacked on top of each other and the bottom material is also sandwiched and sealed.
  • the packaging bag accommodates contents such as foods and medicines, and can be subjected to heat sterilization treatment such as retort treatment and boiling treatment.
  • Retort processing is a method that sterilizes microorganisms such as mold, yeast, and bacteria under pressure in order to generally preserve foods, medicines, etc.
  • packaging bags containing foods, etc. are subjected to pressure sterilization treatment at 105 to 140°C and 0.15 to 0.30 MPa for 10 to 120 minutes.
  • pressure sterilization treatment at 105 to 140°C and 0.15 to 0.30 MPa for 10 to 120 minutes.
  • retort devices There are two types of retort devices: a steam type that uses heated steam and a hot water type that uses pressurized heated water.
  • Boiling is a method of sterilizing foods, medicines, etc. with moist heat to preserve them.
  • the boiling process is usually performed at 100°C or lower using a hot water bath. More specifically, a packaging bag containing food or the like is subjected to moist heat sterilization treatment at 60 to 100° C. under atmospheric pressure for 10 to 120 minutes, depending on the contents.
  • moist heat sterilization treatment at 60 to 100° C. under atmospheric pressure for 10 to 120 minutes, depending on the contents.
  • the above-mentioned packaging bag is difficult to curl due to retort treatment at a high temperature of 125° C. or higher (high retort treatment), and therefore can be particularly suitably used in applications where high retort treatment is performed. Furthermore, the packaging bag has a good appearance because it has less deformation (distortion) and wrinkles due to heat during bag making, and is also excellent in transportability and workability when sealing the contents.
  • OPP-2 was laminated on OPP-1 by a dry lamination method via a two-component adhesive (manufactured by Mitsui Chemicals, Inc., product name: main agent A525/curing agent A52), and then in the same manner.
  • CPP-1 was laminated on top of OPP-2.
  • the MD direction of OPP-1, OPP-2, and CPP-1 were made to match.
  • a laminate having a laminated structure of OPP-1 (base material layer)/S (adhesive layer)/OPP-2 (intermediate layer)/S (adhesive layer)/CPP-1 (sealant layer) is manufactured. did.
  • the content of polypropylene in the obtained laminates was 90% by mass or more, and the thickness of the adhesive layer (S) was 3.1 ⁇ m in all cases.
  • Example 2 (Preparation of composition for forming coat layer) Acrylic polyol and tolylene diisocyanate are mixed so that the number of NCO groups in tolylene diisocyanate is equal to the number of OH groups in acrylic polyol, and the total solid content (total amount of acrylic polyol and tolylene diisocyanate) is ) was diluted with ethyl acetate to 5% by mass. Further, ⁇ -(3,4 epoxycyclohexyl)trimethoxysilane was added to the diluted mixed solution in an amount of 5 parts by mass based on 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed. By doing so, a composition for forming a coat layer (anchor coating agent) was prepared.
  • composition for forming a gas barrier coating layer was prepared by mixing the following liquids A, B, and C at a mass ratio of 65/25/10, respectively.
  • Solution A 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of tetraethoxysilane (Si(OC 2 H 5 ) 4 ) and 10 g of methanol, and the mixture was stirred for 30 minutes to be hydrolyzed, resulting in a solid content of 5% by mass (SiO 2 (conversion) hydrolysis solution.
  • Solution B 5% by mass water/methanol solution of polyvinyl alcohol (mass ratio of water:methanol is 95:5).
  • Solution C 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate was diluted to a solid content of 5% by mass with a mixed solution of water/isopropyl alcohol (mass ratio of water:isopropyl alcohol was 1:1). Hydrolysis solution.
  • the above coating layer forming composition was applied to the corona-treated surface of OPP-2, which had been corona-treated on one side, by a gravure roll coating method, dried and cured at 60° C., and the coating amount was 0.1 g.
  • a coating layer (C1) made of an acrylic polyurethane resin having a diameter of /m 2 was formed.
  • a transparent inorganic oxide layer (G1) made of silicon oxide and having a thickness of 30 nm was formed using a vacuum evaporation apparatus using an electron beam heating method.
  • As the inorganic oxide layer (G1) a silica vapor-deposited layer having an O/Si ratio of 1.8 was formed by adjusting the type of vapor-deposited material.
  • the O/Si ratio was determined using an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV), using non-monochromatic MgK ⁇ (1253.6 eV) as the X-ray source, and 100 W (10 kV- The measurement was performed with an X-ray output of 10 mA). Quantitative analysis to determine the O/Si ratio was performed using relative sensitivity factors of 2.28 for O1s and 0.9 for Si2p, respectively.
  • the above composition for forming a gas barrier coating layer is applied onto the inorganic oxide layer (G1) by a gravure roll coating method, and dried by heating in an oven at a tension of 20 N/m and a drying temperature of 120°C.
  • a gas barrier coating layer (G2) having a thickness of 0.5 ⁇ m was formed. Thereby, a gas barrier film serving as an intermediate layer was obtained.
  • OPP-1 On top of the gas barrier coating layer (G2) of the gas barrier film, OPP-1, which will serve as the base material layer, is applied via a two-component adhesive (manufactured by Mitsui Chemicals, Inc., product name: base material A525/curing agent A52). After laminating by a dry lamination method, CPP-1 to serve as a sealant layer was similarly laminated on OPP-2 of the gas barrier film. At this time, the MD direction of OPP-1, OPP-2, and CPP-1 were made to match.
  • OPP-1 base material layer
  • S adheresive layer
  • G2 gas barrier coating layer
  • G1 organic oxide layer
  • C1 coat layer
  • OPP-2 adherive layer
  • Example 3 CPP-1 was laminated onto OPP-1 by a dry lamination method using a two-component adhesive (manufactured by Mitsui Chemicals, Inc., trade name: base resin A525/curing agent A52). At this time, the MD direction of OPP-1 and the MD direction of CPP-1 were made to match. In this way, the laminate of Example 3 (the laminate having the laminate structure shown in Table 3) was manufactured. The content of polypropylene in the obtained laminate was 90% by mass or more, and the thickness of the adhesive layer (S) was 3.1 ⁇ m.
  • a two-component adhesive manufactured by Mitsui Chemicals, Inc., trade name: base resin A525/curing agent A52.
  • Example 4 A laminate of Example 4 (a laminate having the laminate structure shown in Table 3) was produced in the same manner as in Example 3 except that CPP-3 was used instead of CPP-1.
  • Example 5 (Preparation of composition for forming coat layer) By mixing Takelac WPB-341 (manufactured by Mitsui Chemicals Co., Ltd.) and isocyanate silane KBE-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) at a solid content ratio of 9:1, a composition for forming a coating layer is formed. I prepared something.
  • the above coating layer-forming composition was applied to the surface of OPP-2 by gravure roll coating, dried and cured at 60°C, and the acid group-containing polyurethane and polyamine were coated in an amount of 1.0 g/m 2 .
  • a coating layer (C2) made of a polyurethane resin was formed.
  • a transparent inorganic oxide layer (G1) made of silicon oxide and having a thickness of 30 nm was formed on the coating layer (C2). Thereby, a gas barrier film serving as an intermediate layer was obtained.
  • Example 5 The laminate of Example 5 was prepared in the same manner as in "Preparation of laminate” of Example 2, except that the gas barrier film prepared above was used and CPP-3 was used instead of CPP-1. (A laminate having a laminate structure shown in Table 3) was manufactured.
  • Example 6 A laminate of Example 6 (a laminate having the laminate structure shown in Table 3) was produced in the same manner as in Example 1 except that OPP-1 was used instead of OPP-2.
  • Comparative Example 1 A laminate of Comparative Example 1 (a laminate having the laminate structure shown in Table 3) was produced in the same manner as in Example 1 except that OPP-3 was used instead of OPP-1.
  • Comparative Example 2 A laminate of Comparative Example 2 (a laminate having the laminate structure shown in Table 3) was produced in the same manner as in Example 1 except that CPP-2 was used instead of CPP-1.
  • Examples 7 to 10 and Comparative Examples 3 to 4> By using the biaxially oriented polypropylene films (OPP-3 to OPP-8) listed in Table 3 instead of OPP-1 and by changing the coating amount of the composition for forming a gas barrier coating layer, the thickness Examples 7 to 10 and comparative samples were prepared in the same manner as in Example 1, except that a gas barrier coating layer (G3) with a thickness of 0.3 ⁇ m was formed in place of the gas barrier coating layer (G2) with a thickness of 0.5 ⁇ m.
  • the laminates of Examples 3 and 4 (laminates having the laminate structure shown in Table 3) were manufactured.
  • ⁇ Analysis 1 Measurement of crystallinity>
  • the laminates obtained in Examples and Comparative Examples were used as measurement samples, and the biaxially oriented polypropylene films (OPP1, OPP-3 to OPP-7) constituting the base layer were measured by oblique incidence X-ray diffraction method under the following conditions. The crystallinity in the MD direction and the TD direction was measured.
  • the X-ray irradiation device and the detector are arranged in a direction perpendicular to the MD direction, and when measuring the degree of crystallinity in the TD direction, the The measurement was performed by arranging the irradiation device and the detector so that they were aligned in a direction perpendicular to the TD direction. The results are shown in Table 3.
  • Measuring device X-ray diffraction device (manufactured by Rigaku Co., Ltd., product name: RINT TTR III)
  • Optical system Parallel method (detector: scintillation counter, application: small angle, target: sample surface) Scanning axis: 2 ⁇ / ⁇ Measurement method: continuous counting unit: cps Starting angle: 3° (approximate) End angle: 35° Sampling width: 0.02° Scan speed: 4°/min Voltage: 50kV Current: 300mA Divergent vertical slit: 10mm Scattering slit: open Light receiving slit: open
  • ⁇ Analysis 2 Measurement of melting point>
  • the melting point (melting peak temperature) of the biaxially stretched polypropylene film constituting the base layer was measured by differential scanning calorimetry (DSC) using the method shown below.
  • DSC differential scanning calorimetry
  • the biaxially oriented polypropylene films (OPP-1, OPP-3 to OPP-7) serving as the base material layer were peeled off from the laminates produced in Examples and Comparative Examples to prepare measurement samples.
  • heat treatment was performed under the following conditions (i), and then differential scanning calorimetry was performed under the following conditions (ii) to measure the melting point (melting peak temperature) after the heat treatment.
  • differential scanning calorimetry was performed under the conditions (iii) below to measure the melting point (melting peak temperature) before heat treatment.
  • melting peak temperature melting peak temperature
  • Table 3 As the differential scanning calorimeter, DSC7000X (trade name) manufactured by Hitachi High-Tech Science Co., Ltd. was used.
  • the temperature was raised from 25°C to 230°C at a rate of 10°C/min, held at 230°C for 2 minutes, and then lowered from 230°C to 25°C at a rate of 10°C/min, and at 25°C for 5 minutes. Hold for minutes.
  • ⁇ Evaluation 1 Deformation amount during bag making (quantitative evaluation)> The amount of deformation of the laminates obtained in Examples and Comparative Examples during bag making (heat sealing) was evaluated according to the following procedure.
  • (a1) The laminate was cut into a square shape of 150 mm x 150 mm to prepare a sample for an evaluation test. Two samples of this were prepared.
  • (b1) After stacking the two samples so that the sealant layer sides were aligned, the four sides were heat-sealed by heating with a heat-seal bar set at a temperature of 160°C for 0.3 seconds at a surface pressure of 1.0 MPa. . At this time, the seal width (width in the direction perpendicular to one side of the square) was 10 mm.
  • the heat seal bar used had an upper side made of metal and a lower side made of silicon.
  • (c1) After heat-sealing, leave the obtained laminated sample (evaluation pouch) at room temperature (25°C) for 30 minutes, then place it on a surface plate, and use a metal ruler to measure the four sides of the evaluation pouch. The height of lift from the board was measured. The maximum value of the lifting heights on the four sides was recorded as the lifting height (X) of the evaluation pouch, and the amount of deformation was evaluated based on the following criteria. The results are shown in Table 4. [standard] A: Height (X) is 10 mm or less B: Height (X) is greater than 10 mm
  • FIGS. 5(a) to 5(c) are cross-sectional views of the sealed portion of the pouch, and are schematic diagrams showing the state of distortion of the pouch after heat sealing.
  • the pouch shown in FIG. 5(a) is evaluated to have almost no distortion and is rated as "A” above.
  • the pouch shown in FIG. 5(b) is evaluated to have small distortion and is rated as "B” above.
  • the pouch shown in FIG. 5(c) is evaluated to have large distortion and is rated as "C” above.
  • the pouch 700 is placed on the desk 800.
  • ⁇ Evaluation 3 Whitening during bag making> The sealed portion of the pouch prepared in Evaluation 2 above was visually observed to see if it had turned white, and evaluated based on the following criteria. The results are shown in Table 4. A: No whitening is observed. B: Slight whitening that is visible when seen through is confirmed. C: Clear whitening is observed.
  • ⁇ Evaluation 5 Amount of curl during high retort processing> The amount of curl of the laminates obtained in Examples and Comparative Examples when subjected to high retort treatment was evaluated according to the following procedure.
  • SYMBOLS 11 Base material layer, 12... Sealant layer, 13... Intermediate layer, 14... First polypropylene film, 15... Third polypropylene film, 16... Coat layer, 17... Inorganic oxide layer, 18... Gas barrier coating layer , 100A, 100B...laminate, S...adhesive layer.

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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Laminated Bodies (AREA)

Abstract

L'invention concerne un stratifié d'emballage (100A) composé d'au moins 90 % en masse de polypropylène, ledit stratifié d'emballage (100A) comprenant au moins une couche de substrat (11) qui comporte un premier film de polypropylène et une couche d'étanchéité (12) qui comporte un second film de polypropylène, le premier film de polypropylène étant un film de polypropylène orienté ; le premier film de polypropylène et le second film de polypropylène étant positionnés de telle sorte que leurs MD respectifs correspondent sensiblement ; le retrait thermique RMD1 dans le MD du premier film de polypropylène n'étant pas supérieur à 10 % ; le retrait thermique RTD1 dans le TD du premier film de polypropylène n'étant pas supérieur à 12 % ; et le retrait thermique RTD2 dans le TD du second film de polypropylène étant inférieur au retrait thermique RTD1 mais pas inférieur à 0,5 %.
PCT/JP2023/020833 2022-06-09 2023-06-05 Stratifié d'emballage et sac d'emballage WO2023238825A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09290477A (ja) * 1996-03-01 1997-11-11 Toppan Printing Co Ltd バリア性フィルムおよびそれを用いた包装材料
JP2018089567A (ja) * 2016-12-01 2018-06-14 凸版印刷株式会社 ガスバリア積層体及びその製造方法
WO2019065306A1 (fr) * 2017-09-26 2019-04-04 東洋紡株式会社 Film stratifié à base de polypropylène
JP2021020391A (ja) * 2019-07-29 2021-02-18 凸版印刷株式会社 積層体及び包装袋
JP2021178974A (ja) * 2018-12-28 2021-11-18 東洋紡株式会社 二軸配向ポリプロピレンフィルム

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09290477A (ja) * 1996-03-01 1997-11-11 Toppan Printing Co Ltd バリア性フィルムおよびそれを用いた包装材料
JP2018089567A (ja) * 2016-12-01 2018-06-14 凸版印刷株式会社 ガスバリア積層体及びその製造方法
WO2019065306A1 (fr) * 2017-09-26 2019-04-04 東洋紡株式会社 Film stratifié à base de polypropylène
JP2021178974A (ja) * 2018-12-28 2021-11-18 東洋紡株式会社 二軸配向ポリプロピレンフィルム
JP2021020391A (ja) * 2019-07-29 2021-02-18 凸版印刷株式会社 積層体及び包装袋

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